CEO Elon Musk had originally said that the company would reveal a prototype of the vehicle in September. He then pushed the reveal date back to October 26. And then, in October, Musk delayed the event date yet again so that Tesla could focus on Model 3 production, which has been lagging, and ramp up battery production for Puerto Rico.

Besides the reveal date, Musk hasn't said much about the upcoming vehicle. However, some details have leaked about what we might see.

1/

Tesla has been working with truck makers on the vehicle's design.

"We are showing off a working prototype at the end of September, but we have shown it to people who buy heavy-duty trucking, and they all love it. They just want to know how many can they buy and how soon," Musk said during Tesla's annual shareholder meeting, hosted in July at the Computer History Museum in Mountain View, California.

"We are getting them closely involved in the design process," he added.

Tesla is including the companies in the design process because it helps ensure their needs are met, Musk said.

2/

Tesla may announce some of its trucking partners at the event.

Two trucks demonstrating "platooning" technology.
Thomson Reuters

Because Tesla has already said it has been working with trucking companies on the design, it's possible the automaker could share who some of these partners are.

They could include large truck carriers as well as shippers, according to a recent note from Morgan Stanley analysts Ravi Shanker and Adam Jonas. Tesla could also be working with the trucking companies Schneider National and XPO, as well as FedEx, according to Jonas.

3/

Tesla should reach full-scale production for the big-rig sometime in 2019.

Benjamin Zhang/Business Insider

Musk also said the company would most likely reach full-scale production for the truck in 18 months to two years.

4/

And deliveries could begin in 2020.

Tesla Motors

The big-rig truck could go on sale as soon as 2020, according to the Morgan Stanley analysts.

5/

The truck may have a range of 300 miles per charge.

REUTERS/Robert Galbraith

With a full charge, the truck will have a range of about 200 to 300 miles with an average payload, according to a Reuters report that cited an executive for the fleet operator that met with Tesla.

To help put that into perspective, conventional diesel-powered trucks can travel up to 1,000 miles on a full tank.

6/

Tesla could introduce a battery-swapping business or ultrafast recharging to help with the truck's range.

Green Car Reports

To compete with traditional diesel trucks, Tesla may offer new charging solutions.

"Tesla will have to clearly address these issues at the event to be able to sell the idea of an electric semi-truck to a deeply skeptical industry," Jonas and Shanker said in the note.

The analysts said the company was unlikely to include a more-than-1,000-kilowatt-hour battery, which would provide a range of 600 to 700 miles, because it would be too expensive.

"Instead, we believe that Tesla would choose to put in a smaller battery (around 250-300 kWh) and choose to solve the range problem either through optional battery swapping or very rapid supercharging/flash charging," Jonas and Shanker said.

7/

It could have self-driving technology similar to Autopilot.

The truck is expected to have self-driving technology that allows it to drive autonomously while traveling in platoons, according to a Reuters report that cited an email discussion between Tesla and the Nevada Department of Motor Vehicles.

Tesla, though, said in a statement that it doesn't comment on speculation.

11/

The truck will have some impressive specs.

While Musk hasn't confirmed any details about the truck, he did say that its specs actually beat everything he has seen reported so far. This could mean that the range is greater than 300 miles per charge.